Mirror MS_KERNMOUNT in ->mnt_flags

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/namespace.c

@@ -1701,7 +1701,7 @@ int do_add_mount(struct vfsmount *newmnt, struct path *path,
 {
 	int err;
 
-	mnt_flags &= ~(MNT_SHARED | MNT_WRITE_HOLD);
+	mnt_flags &= ~(MNT_SHARED | MNT_WRITE_HOLD | MNT_INTERNAL);
 
 	down_write(&namespace_sem);
 	/* Something was mounted here while we slept */

fs/super.c

@@ -937,6 +937,9 @@ vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void
 	if (!mnt)
 		goto out;
 
+	if (flags & MS_KERNMOUNT)
+		mnt->mnt_flags = MNT_INTERNAL;
+
 	if (data && !(type->fs_flags & FS_BINARY_MOUNTDATA)) {
 		secdata = alloc_secdata();
 		if (!secdata)

include/linux/mount.h

@@ -45,6 +45,8 @@ struct mnt_namespace;
 #define MNT_PROPAGATION_MASK	(MNT_SHARED | MNT_UNBINDABLE)
 
 
+#define MNT_INTERNAL	0x4000
+
 struct vfsmount {
 	struct list_head mnt_hash;
 	struct vfsmount *mnt_parent;	/* fs we are mounted on */